Infections acquired from contaminated food and food products are becoming more and more frequent. For example, a 1987 study of group health patients with diarrhea in the Puget Sound area showed an unexpectedly high incidence of E. coli 0157:H7 (MacDonald K L, et al, JAMA 259:3567-3570, 1987). Eighty-nine percent of the patients with E. coli did not have a history of eating undercooked meat. In 1993 there was an E. coli 0157:H7 epidemic traced to undercooked hamburger meat in Washington state. Four children died and several others suffered permanent kidney damage. Much of this contamination has been traced to the food preparation process, although two of the Washington E. coli cases did not come from direct consumption of contaminated hamburgers and are assumed to have been acquired by indirect contact. Other bacteria causing gastroenteritis and diarrhea include Campylobacter, Salmonella and Shigella species. Salmonella typhimurium has been reported in watermelon, dried milk, and baby formula and led to severe cases of diarrhea. Salmonella enteritides is showing a marked increase in incidence due to contamination of eggs and egg products. With the apparent proliferation of illnesses caused by ingestion of pathogenic organisms, there is a greater potential for cross contamination of foods such as from cutting boards and other work surfaces that are used for processing and/or preparing poultry, beef, or pork.
A number of recent studies have shown that bacterial contamination of cutting boards that come into direct or indirect contact with food is due principally to bacterial biofilms and not planktonic bacteria. Planktonic bacteria are single organisms moving in a fluid while a bacterial biofilm consists of colonies of bacteria surrounded by a mucous, glycopolysaccharide coat which is adherent to surfaces. Most of the studies of classical microbiology starting with Louis Pasteur have been performed on bacteria growing in enriched liquid culture media or on solidified enriched culture media in petri dishes. These enriched culture conditions encourage bacteria to grow in planktonic form. In nature, bacteria exist in a more hostile environment and form biofilms. One example of a biofilm is Legionella bacteria in air conditioner cooling towers which is responsible for Legionaries disease. Bacteria on wood cutting boards rapidly form biofilms which are not recovered by routine culture methods and are difficult to remove from contaminated areas.
While it is generally accepted that cutting boards can be cleaned using conventional methods such as hot water and detergents and/or disinfectants such as quaternary ammonium compounds, a study published in January 1994 showed that there were living bacteria in biofilms adherent to wood and plastic cutting boards and suggested these bacteria were a potential source for household and commercial food contamination. This article concluded that there is a need for development of better ways to remove bacterial biofilms from cutting surfaces (Abrishami, Tall et al "Bacterial Adherence and Viability on Cutting Board Surfaces," J Food Safety 14:153-172, 1994.)